Patent GB 1110287 discloses a sheet made of thermoplastic resin, which is extruded with a corrugated profile and on which corrugations are provided in a direction that is substantially parallel to the extrusion direction.
A substantially flat sheet is connected to the resulting corrugated sheet, for example by lamination; such flat sheet can be made of the most disparate materials and can be obtained for example by means of expanded plastic material.
This embodiment has the drawback of producing a manufactured article that is difficult to store, since the coupled sheet that is provided cannot be rolled up because the corrugations lie substantially parallel to the longitudinal extension of the ribbon.
Because of this problem, the article in this embodiment has not achieved an acceptable diffusion among users, since it was not practically possible to perform industrial-level production.